javascript, passing parameters to a callback inside a closure that is inside a function

Question

I'm stuck with a problem related to db.transaction().objectStore.onsuccess i need to get back the data to create a table with the results.

As first test, i try to return data from the call after the cursor has been read completely:

function readAll() {
  var resultData=[];
  var objectStore = db.transaction("employee").objectStore("employee");
  objectStore.openCursor().onsuccess = function(event, args) {                          
    var cursor = event.target.result;               
    if (cursor){
        resultData.push(cursor.value);                  
        cursor.continue();
    }else{
       return resultData;
            }             
 };
}

but this doesn't work because the asynchronous nature of the indexedDB

so, after some thinking i try to use a callback...

function readAll(callBackFunction) {
  var resultData=[];
  var objectStore = db.transaction("employee").objectStore("employee");
  objectStore.openCursor().onsuccess = function(event, args) {                          
    var cursor = event.target.result;               
    if (cursor){
        resultData.push(cursor.value);                  
        cursor.continue();
    }else{
        callBackFunction;
    }             
 };
}

this seem partially work because the callback will be called but I'm not able to pass parameters to the callback function because parameters array is empty inside the onsuccess=function() (as i can understand parameters are bind to readAll function) and I'm not able to pass it inside the onsuccess. So how can i pass parameters to callback?

There is another option different from the callback?

thank you

UPDATE

My problem is that i need to pass more parameters other than the result, like "table_id", "header" etc. so i need to pass some parameters to readAll and pass those parameters to callback, something like: readAll(callBackFunction, "table_id", "header_array")

I've already tested below solution that doesn't work:

function readAll(callBackFunction) {
  var resultData=[];
  var objectStore = db.transaction("employee").objectStore("employee");
  objectStore.openCursor().onsuccess = function(event, args) {                          
    var cursor = event.target.result;               
    if (cursor){
        resultData.push(cursor.value);                  
        cursor.continue();
    }else{
        callBackFunction(parameters[1], parameters[2], resultData);
    }             
 };
}

readAll(createTable, 'table_id', ['username', 'email']);

the problem is that the parameters array is empty inside the closure

UPDATE 2

arguments array is empty inside the closure but is ok outside. If i move the callback outside the closure, I've have parameters but not data..

UPDATE 3

Also adding all parameters to function seem not working.

    function readAll(callback, header, idName, classToAdd, resultData) {
                    var resultData=[];
                    var objectStore = db.transaction("employee").objectStore("employee");
                        objectStore.openCursor().onsuccess = function(event) {                          
                    var cursor = event.target.result;               
                    if (cursor){
                        resultData.push(cursor.value);
                        //alert("Name for id " + cursor.key + " is " + cursor.value.name + ", Age: " + cursor.value.age + ", Email: " + cursor.value.email);
                        cursor.continue();
                    }else{
//HERE ALL ARGUMENTS ARE EMPTY BUT resultData Exists!

                     callback(arguments[1], arguments[2], arguments[3], arguments[4], resultData);
                    }             
               };
//HERE ALL ARGUMENTS EXISTS EXCEPT resultData!
                     callback(arguments[1], arguments[2], arguments[3], arguments[4], resultData);

}

Answer 1

You could just invoke the function like

callBackFunction(resultData);

so that the function you passed receive the results. In the function declaration you should have such a parameter:

function callbackFunction(results) { 
   //create the table
}

You would pass it to readAll() like

readAll(callbackFunction);

EDIT:

According to your edit. You have to add extra parameters to your function declaration

function readAll(callBackFunction, table_id, data) {
   // ... code
  callBackFunction(table_id, data, resultData);
}

Then you can declare 2 more parameters in your createTable function and they will receive "table_id" and "data".

Answer 2

after some time I'm back to this problem and find a solution that work. The problem is that I initialize the objectStore in a single call.

var objectStore = db.transaction("employee").objectStore("employee");

if I divide this call in two different pieces:

var transaction = db.transaction("employee");
var objectStore = transaction.objectStore("employee");

everything work as expected.